Heat transfer apparatus



April 16, W ASTLE amarA TR'ANSFER APPARATUS E11-ed oct. 22, 193.7

2 .Sheets-Sheet l 7'0 ,fida/59A Tae April16, 1940. w ASTLE 2,197,118 I HEAT TRANSFER APPARATUS Filed oct. 22, 1957 2 sheets-.sheet 2 Patented Apri.l 16, 1940 UNITED STATES PATENT OFFICE 191,113 naar 'marasma Arrm'rns wmim Ame, cmg, n1. Application october 2z, 1931, serial No. 1711.397

One of the objects of my invention is to provide l improved means for insuring that the milk treated is heated to a temperature conforming to legal requirements or to a desired temperature.

A further object of my invention is to provide apparatus, as indicated above, having diversion valve means whereby the milk, after having passed through the heating section, is caused to be returned through the heating section if the temperature of the heated milk is below the legal temperature requirements or below the desired temperature.

A further object of my invention is to proyide apparatus as indicated above, in which leak pro-l tection means are provided in the diversion valve means for preventing the contamination of milk that has been raised to the predetermined temperature by milk below the predetermined teniperature.

Aiurther object of my invention is' to provide apparatus as indicated above, in which the milk .that is to beheated will always beata less pressure in the regenerative section than will the milk which has been heated tothe required temperature. c

Further objects and advantages of the invention will be apparent from, the description and claim. 4, In the drawings, in which an embodiment of my invention is shown, v e

Figure 1 is a diagrammatic view showing the heating apparatus and the uid circulation;

Fig. 2 is an axial section through the diversion valve; and

Fig. 3 is a somewhat diagrammatic view showing four heat exchange plates and indicating the fluid now. 'l

Referring to the drawings in detail, the construction shown comprises a regenerative .heat transfer apparatus Ivior preheatlng the raw milk and cooling the heated milk, means 2 from which milk is supplied to the regenerative apparatus to be preheated, heating apparatus 3 to`which the preheated:v milk from the regenerativeA apparatus is suppliedfa lholding apparatus 4 in which the milk from the heater 3 may be held for a desired length of time, a diversion valve construction l controlled by a thermostatic bulb 8 subjected to the temperature of the milk delivered from the holder 4 for selectively controlling the flow of milk from the holder to cause the milk from the holder to be delivered to the regenerative appa- 5 `ratusl if it is up to the desired predetermined temperature and to cause it to be recirculated through the heater 3 if it is below the desired temperature, and a pump I for effecting the circulation of the milk throughA the regenerator I, V1I) heater 3, holder 4, and diversion valve 5.

In one position of the diversion valve 5, the milk from the holder 4 is delivered through the pipe 8 to the regenerator l, and in another position of the diversion valve the milk fromthe 1li holder 4 is redelivered to the pump 'I through the pipe 3, to be again recirculated through the heater l3 and holder 4 until it is brought up to the desired temperature.

The flow of raw milk through the regenerator I is indicated dlagrammatically 20 by the line' 9*; the flow through the heater by the line 9b, and the ow through the holder by the line Se. The ow of the heated milk from the pipe through the regenerator is indicated l diagrammatically by the line Sii. 25

The pump 1, thermostatic bulb 6, control mechanism for the diversion valve 5, heater 3, holder 4, and regenerator I may be of any suitable type. The plate construction used in the heater 3 and regenerator I, if desired, may be similar to 30 that shown in my copending application Serial No. 161,265, filed August 27, 1937.

The thermostatic bulb 6 may control a relay I0 which may, in turn, control a pneumatic actuator II for the diversion valve 5. The construction of thethermostatic bulb 6" and lcontrol mechanism isy such that if the milk from the holder is below the desired temperature, the diversion valve stem I2 will be in its raised position to cause recirculation, and if the temperature vof the milk from 40 trolling the milk level'in the milk supply 2, thus making the head or pressure on the raw milk supply less than the head or pressure on the heated vmilk delivered from the regenerative set. The I5- pump 1 will draw the milk from the milk supply 2 through the regenerative apparatus.

The circulation of milk is from the raw milk supply 2, through the pipe I3 to the regenerative set, thence through the pipe from the regenerative set to the pump, thence through the pipe I4 to the pump 1, thence through the pipe I5 to the heater 3 and holder 4, and thence through the pipe I6 to the diversion valve 5. From the diversion valve the flow, depending on the position of the diversion valve, may be either from the diversion valve to the regenerative set I, through the pipe 8, if the milk is up to the desired temperature, or through the pipe 9 from the diversion valve 5 to the pump 1, if the temperature is below that desired.

'Ihe diversion valve structure shown in detail in Fig. 2 comprises a casing I1 having an inlet I8 connected with the pipe I6 from the holder, an outlet I9 connected with the pipe 8 leading to the regenerative set I, an outlet 20 connected with the pipe 9 leading to the pump 1 for recirculation, and a two-way valve 2| which, in one position, closes the port 22 leading to the outlet I9 to the regenerative set and opens the port 23 leading to the pump 1 and which, in another position, opens the port 22 leading to the regenerative set I and closes the port 23 leading to the pump.

In order to prevent any possibility of contamination of milk which has been raised to the desired temperature from the milk which has not been raised to the desired temperature, a drain valve construction is provided, operative when the valve 2I is in its upper position, the drain valve port 24 being located between two concentric lines of cut-olf so that any milk below the desired temperature which may possibly seep past the first annular cut-oil' of the valve will escape past this drainage valve rather than past the second line of cut-olf leading to the passage to the regenerative set. 'I'his drainage valve vcomprises a spring-pressed plunger having a conical valve portion 25 cooperating with the conical valve seat 24 which, as indicated above, lies between two concentric annular conical valve seats 28 and 21 yagainst which the annular valve surfaces 28 and 29 of the upper valve member 38 seat, respectively. Any leakage which may seep past the first line of cut-oi at 21 and past the conical valve seat 24 may escape through the discharge opening 3|. The drain valve is opened by the engagement of a portion of the valve 38 with the end of the conical portion 25 of the drainage valve when the valve 30 is in its raised position. When the valve portions 28 and 29 are seated, an annular chamber is provided between the annular lines of cut-olf, and any milk which mayseep into this chamber will escape through the port3I. The valve portion 30 may be a resilient band which can yield so that both valve portions 28 and 29 may seat properly.

In operation, raw milk is supplied to the regenerative set I from the raw milk supply 2. The pump 1 is put in operation to draw the milk from .the supply tank 2 through the regenerative set I and deliver it to the heating and holding sections. If the milk is up to the required tern-V perature, it will flow through the diversion valve 5 and pipe 8 to the regenerative set I, but if it is not up to the required temperature, it will be directed to the pump 1 through the pipe 9, to

Vbe again recirculated through the heating and 'holding sections.A 3 and 4 until it is up to the desired temperature.

As previously stated, the pressure of the heated milkin the regenerative set will be greater than the pressure of the raw milk to be heated, so that there will be no danger of the raw milk leaking into the passages for the heated milk.

Also, as previously stated, the plate construction may be similar to that shown in my copending application Serial No. 161,265, iiled August 27, 1937. This construction is shown in detail in Fig. 3. Asv shown therein, plates 38B, 38h, 38, and 38d may be substantially identical in construction, except as to the porting arrangement, alternate plates being reversed, end fory end, to venable the countercurrent flow.

Referring to Fig. 3, and rst to the front plate 38a, this may be of thin sheet metal, the upper and lower portions of the plate being substantially symmetrical about a horizontal'center line, the lm ilow along the lower half of the plate being duplicated by the lm flow along the upper half of rthe plate. 'Ihe front face of the plate is provided with now-directing partitions 45 which will engage the surface of an adjacent plate or of an adjacent terminal block to confine the -flow of fluid entering at A to a circuitous path A' leading away from the place of entrance A to the right and thence back to the left to a dis-A charge place A2 adjacent the place of entrance A. Similarly, fluid introduced at B to the iront face of the plate 38b will flow on a circuitous path B' away from the place of entrance B to the right and thence back to a place of discharge B2 adjacent the place of entrance. In the arrangement shown in Fig. 3, the milk entering is divided at A into two streams A' and C', one of which (A') flows as described in a circuitous path along the front face of the rst plate 38HL and thence through aligned ports in the plates 38, 38h, 38, and 389,'and the other stream C' of which ows through gasketed ports 46a and 46 to the entrance place C vbetween the second plate 38b and the third plate 38 from whence it flows in a circuitous path C', first to the right away from the place of entrance C, thence to the left back to a discharge place C2 adjacent the place of entrance C, where it unites with the stream A',v

and thence ilows through the gasketed ports 41 and 41d to a place of discharge, which is in transverse alignment withA the place of entrance so that if desired the flowing fluid can be caused to repeat its ow through another set of four plates, similar to the plates shown in Fig. 3.

The other fluid, with respect to which transfer of heat is to be made, may enter the ilow space between the third plate 38 and the fourth plate 38d through the port 48d in the4 fourth plate 38d, as indicated bythe arrows, the flow separating at this point, part of the iluid being directed in a circuitous path D between the third vand fourth plates and part of it flowing along the path B through. the ports 48 and 48b in the third plate 38 and second plate 38D, respectively, into the flow space between the rst plate 38a and second plate 38, where it flows in a circuitousfpath B', and thence out through the i gasketed port 49a inthe rst plate 38 where the flow may be shifted into transverse alignment Withthe port of entry 48d in the fourth plate 38 so that, if desired, this fluid may be caused to pass through another set of four plates in front of the four plates 'shown and similar in construction and arrangement to the four'plates shown.

`It will be seen that the fluid ow divides at 48d,

one division owing along the path D' between the third plate 38 and fourth plate 38d and the r the iirst plate 38B and second plate 88", and that the discharge from the ilow space between the third plate 38's and fourth plate 38l and the discharge from the flow space between the lrst plate 38* and second plate 38I unite at 50 'and are discharged together through the discharge port 49' in the front plate. Similarly, the other uid divides at A into Atwo streams, A' and C', one of which ows in a'circuitous path along the front face of the front plate andthe other` di'F vision C'v of which flows between the second and third plates, and these two divisions A' and C' again unite at C2 and are discharged through the discharge openings 4`|c and 41d in the third and fourth plates.

The stream A' flows successively through ports 41, 41h, 41e and 41d. `The stream C branching oit from the stream A' iiows successively through ports 46a and 46b over the surface of the plate 38c and reunites with the stream A' at C. The stream D entering the interplate iiow space at 484 iiows over the surface of the plate 88d and then successively through the ports 48, 49 and 48. The stream B' branching on' from the stream E ilows successively through the ports 48 and 48b and over the plate 4'8b to the point 50 where it reunites with the stream D' and is discharged through the port 48'.

Means for controlling the iiow may be provided in a suitable manner, such as embossing the plates to provide ridges 45 which will engage an adjacent plat'e`to provide the' desired flow passages. It is not necessary that these guide means or partitions be gasketed as a slight leakage will f have no detrimental effect, as it is ,not necessary to maintain absolute separation between the illms flowing in the circuitous paths on opposite sides of the guide means or partitions It will beseen that this construction enables countercurrent iiow to be maintained on opposite sides of all of the plates, this being accomplished by guiding a fluid nlm to ilow in a circuitous path away from a place of entrance adjacent one edge of the plate away from the place of introduction and thence back to a discharge place adjacent the place of introduction and providing on the opposite side of the plate a place of introduction adjacent an opposite edge of the plate and guiding another fluid nlm to iiow in a circuitous path away i'rom the place of introduction and back to a point,y adjacent the place of introduction, the path on one side i. the plate being juxtaposed with respect to the path on the opposite side of the plate.

The outer boundary of the interplate flow space is dened by a six-sidedgasket 8| which may be in the form of an endless band of ilexible compressible gasket material surrounding a six-sided ridge i2 struck up from the material of the plate. The intel-plate iiow is excluded from two of the corners ofthe plate to provide room for a triangular gasket construction to enable the through plate now. The gasheting for the through plate .iiowmaybesimilarineonstructiontothesashetingtortheinterplatenow. Thisgasketingcon- I4 of suitable iiexible compressible gasket material stretched around a triangular ridge 55.

Withthis construction, it will be seen that the pressure of raw milk in the regenerator will always be Iless than the pressure of the heated milk in theregenerator, both when the pump 1 is running and when it is stopped. When the pump is lrunning, the raw milk in the regenerator is on the suction side of the pump and the pressure of the raw milk in the 4regenerator is subatmospheric, since the pipes I3 connect Withthe regenerator at its lower side. `When the pump is running, pressure of the heated milk in the regenerator is superatmospheric, since theoutlet for the flow 9d is at the upper side of the regenerator and on the pressure side of the pump 1. Consequently, any leakage of milk past the gaskets while the pump is running will loe` from the heated milk sides of the plates.

When for any reason the pump 1 is stopped, practically all ofthe raw milk in the regenerator drains back into the milk supply 2, due to the construction of the plates 38', 38h, 38, and 38d, and due to the fact that the pipe I3 connects to the lower side of the regenerator. There is thus practically no pressure on the raw milk sides of the plates. milk will not drain from the regenerator, since both vsupply and discharge connections for the h eated milk are on the upper side of the regenerator. Consequently, a static pressure heat will exist on' the heated milk side of the plates of the regenerator so that any leakage of milk past the gaskets will be from the heated milk sides ci the plates to the raw milk side.

Further modifications will be apparent 4to those skilled in the art and it is desired, therefore, that the invention be' limited only by the prior art and the scope of the appended claim. A

Having thus described my invention, what I claim and desire to secure by Letters Patent is: The combination with a milk pasteurizing apparatus comprising a regenerative heat transier apparatus for preheating the raw milk and precooling the heated milk, means for supplying milk tosaid regenerative apparatus to be preheated, and heating apparatus to which the preheated milk from the regenerative apparatus is supplied, oi means, including diversion valve means controlled by the temperature of the heated milk, whereby the heated milk -is caused to On the other hand, the heated be recirculated through the heating apparatus if said heated milk is below a predetermined temperature and is delivered to the regenerative apparatus if its temperature is equal to or greater than the predetermined temperature, said divergence valve means having drainage provisions for preventing leakage of milk which is below a predetermined temperature from mixing with the milk which has previously passed through the valve means on its way to the regenerative apparatus, and means whereby the pressure in the regenerative apparatus of the milk from which heat is to be transferred is greater than the pressure of the milk to which heat isto` be WILHAM ASTLE. 

